1. Field of the Invention
The present invention relates to a packaging article and corresponding blank component for its manufacture.
2. Description of the Prior Art
U.S. Pat. No. 5,009,039 issued Apr. 23, 1991 to B. A. Goldberg describes a method for fabricating a fluid confining tray having a solid, 0.007 to 0.035 inch thick paperboard sheet substrate blank that is fold erected with corner lapping flaps and confined in pairs within a divided blow mold cavity. A segment of continuously extruded polymer parison tube is clamped and sealed within the cavity by closure of the mold halves. Upon expansion and chilling of the parison segment, the divided mold is opened to release two, oppositely facing, laminated tray structures unitized by an unlaminated band of polymer film. The unlaminated polymer band is subsequently trimmed to separate the two open-top, fluid confining tray products.
Except for rolled corners, the Goldberg tray has a flat plane bottom and walls. Although this construction is surprisingly rigid, the plate buckling property of a flat surface remains.
That geometry generally associated with a food serving bowl includes the compound curve structure of a convex lens. The functional strength and durability of such geometry is unsurpassed. Unfortunately, those compound curves that are characteristic of lenticular surfaces are difficult to transform from paperboard sheet due to the low yield capacity of the material. It has little stretch tolerance before bursting or tearing.
An objective of the present invention, therefore, is to provide a substantially lenticular vessel fabricated from paperboard sheet.
Another object of the present invention is to provide a laminated, fluid confining, paperboard vessel having arched sidewalls.
Another object of the invention is to provide an unusually stiff paperboard bowl having a plurality of curved side wall sections jointed by curved, edge-butt joints which, collectively, closely approximates a true, lenticular geometry.